First all-solid pediatric phantom for dual X-ray absorptiometry measurements in infants

Area of Science:

• Medical Physics
• Pediatric Imaging
• Biomedical Engineering

Background:

• Manufacturer-supplied phantoms for dual X-ray absorptiometry (DXA) quality control are typically designed for adults, lacking pediatric-specific whole-body models.
• Accurate assessment of bone mineralization and soft tissue composition in infants using DXA is crucial for monitoring growth and health.

Purpose of the Study:

• To design and validate a novel pediatric phantom for whole-body DXA measurements.
• To evaluate the impact of scan acquisition parameters and software versions on DXA results in pediatric phantoms.

Main Methods:

• Development of five whole-body phantoms ("Inphants") using acrylic, polyvinyl chloride, and aluminum to mimic infant body weight and composition.
• Scanning of "Inphants" using a Hologic QDR 2000, comparing measurements with and without a table pad and using both infant and adult software versions.

Main Results:

• The table pad significantly influenced DXA measurements of fat mass, lean mass, and bone mineral content (BMC) in "Inphants."
• Significant differences were observed in fat mass, lean mass, and BMC depending on the phantom size and software used (infant vs. adult).
• Adult software yielded substantially lower BMC and different fat and lean mass values compared to infant software, necessitating conversion formulae.

Conclusions:

• "Inphants" provide a valuable tool for quality control and standardization of whole-body DXA in infants.
• Established guidelines for scan acquisition and analysis are suggested to improve the accuracy of DXA measurements in young subjects.
• The study highlights the critical need for pediatric-specific phantom development and software considerations in infant DXA assessments.